over a microscopic sea creature. >> and hurricane sandy is a menace. the monster storm is now headed for the united states and it is likely to affect the airlines. >> you want to do it with a great guy. >> the provocative new political ad that some a >>> the world's oceans are already facing an extreme threat from overfishing, but an equally severe problem is just getting attention. the oceans are turning more acidic and it is happening fast. that's bad for the animals who live in the water, of course, but as you will see tonight, it could also be very bad for us. it is staggering, really, but only 5% of the ocean has been explored. that's enough for scientists to know there is trouble underwater. the same fossil fuels polluting the air are also making the ocean more acidic. >> it has incalculable risks associated with it. it may overshadow global warming. >> silvia earl is one of the most represented marine biologists. she was named a living legend by the library of congress. she founded the company that builds submersibles that explore the ocean. she is a fellow at the academy of s